Protease Inhibitor Drugs Research Articles

Anti-HIV-drug and phyto-flavonoid combination against SARS-CoV-2: a molecular docking-simulation base assessment

At the health emergence, no such potent prophylactic therapy is available to control the deadly emerged Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). However, existing antiviral, anti-inflammatory, antimalarial drugs is the only option against SARS-CoV-2, but it may be harmful to patients without more clinical evidence. As an alternative solution, we proposed a newer hypothesis using the selective 10 potent anti-HIV drugs and flavonoid class of phytochemicals from previous reports to use in combination against SARS-CoV-2. Primarily, 10 anti-HIV protease inhibitor drugs and 10 phyto-flavonoids as ligands in molecular docking study against the putative target, the SARS-CoV-2-main protease (Mpro) ID: 6Y2E), as an essential enzyme in viral genome replication. According to molecular docking and drug-ability scores of each ligand, the anti-HIV drug, the darunavir (with a docking score, −10.25 kcal/mol and drug-likeness rating, 0.60) and the quercetin-3-rhamnoside (with a docking score, −10.90 kcal/mol and drug-likeness rating, 0.82) were selected for further analysis in combined effect. Perceptibly, the combined ‘anti-HIV drug and phyto-flavonoid’ docking complex has actively interacted with eight strong H-bonds with stability, briefly elucidated through RMRD-, RMSF- Rg-plots and MM/PBSA-binding energy calculation during 100 ns than the individual against SARS-CoV-2-Mpro. Thus, the ‘anti-HIV-drug-phyto-flavonoid’ combination therapy could be used against SARS-CoV-2 after some experimental validation. Communicated by Ramaswamy H. Sarma

Human Immunodeficiency Virus type 1 Drug Resistance Mutations in Patients Failing Antiretroviral Therapy in Lebanon from 2009 to 2013

Background: Antiretroviral drug resistance remains a significant problem in the clinical management of patients infected with the Human Immunodeficiency Virus type-1. Aim: This study investigates and reports data on the molecular characterization of HIV-1 isolates from patients who are in a state of therapy failure. Methods: This is a retrospective study conducted on 65 patients in therapy failure. Inclusion criteria included patients diagnosed as being in therapy failure between the years 2009 and 2013. We defined ART failure as either a failure to achieve viral suppression or a failure to detect viral loads below 500 copies/mL after virological suppression in at least two plasma samples. We used the published WHO list for surveillance of transmitted resistance and the Stanford HIV Drug Resistance Database to identify drug resistance mutations. Results: 65% of the participants had at least one drug resistance mutation (DRM). 12% of the population sampled had resistance to only one ART class, 32% presented with resistance to two classes of antiretroviral drugs, and 20% had resistance to all three classes of drugs. The prevalence of nucleoside transcriptase inhibitor (NRTI) mutations was 55%, the most common DRM being M184V. The prevalence of non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations was 58%, with the most common mutation being the K103N mutation. The prevalence of protease inhibitors drug resistance mutations was 23%, with mutations V82A and I47V being present in 10% of the study population. Conclusion: Our study is the first molecular characterization of DRM emergence in HIV-1 strains from patients failing antiretroviral therapy in Lebanon. Continuous monitoring of resistance patterns for HIV in the country is necessary to tackle the emergent drug resistance.

The Chiron Approach to (3R,3aS,6aR)-Hexahydrofuro[2,3-b]furan-3-ol, a Key Subunit of HIV-1 Protease Inhibitor Drug, Darunavir.

We describe an enantioselective synthesis of (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-ol which is a key subunit of darunavir, a widely used HIV-1 protease inhibitor drug for the treatment of HIV/AIDS patients. The synthesis was achieved in optically pure form utilizing commercially available sugar derivatives as the starting material. The key steps involve a highly stereoselective substrate-controlled hydrogenation, a Lewis acid catalyzed anomeric reduction of a 1,2-O-isopropylidene-protected glycofuranoside, and a Baeyer-Villiger oxidation of a tetrahydrofuranyl-2-aldehyde derivative. This optically active ligand alcohol was converted to darunavir efficiently.

Synthesis of novel coumarin analogues: Investigation of molecular docking interaction of SARS-CoV-2 proteins with natural and synthetic coumarin analogues and their pharmacokinetics studies.

The severe acute respiratory syndrome coronavirus, identified as SARS-CoV-2, initially established in Wuhan, China at the end of 2019, affects respiratory infections known as COVID-19. In an extraordinary manner, COVID-19 is affecting human life and has transformed a global public health issue into a crisis. Natural products are already recognized owing to the massive advantageous window and efficient antioxidant, antiviral immunomodulatory, and anti-inflammatory belongings. Additionally, the object of the present study was to demonstrate the inhibitory potential of the natural products coumarins and its analogues alongside SARS coronavirus. The present work, focuses on the synthesis of new coumarin analogues and characterized by FT-IR, 1H and 13C NMR, elemental analyses, and mass spectra. The recently synthesised compounds were projected conceptual association for COVID-19 protease and also to explore in anticipation if this protein will help target protease inhibitor drugs such as Calanolide A, Cardatolide A, Collinin, Inophyllum A, Mesuol, Isomesuol, Pteryxin, Rutamarin, Seselin and Suksdorin. The natural coumarin analogues docking scores were compared to standard Hydroxychloroquine. While the 3D module of SARS coronavirus main protease was predicted with the SWISS MODEL web server, as well as biochemical interaction tests were performed with the AutoDock Vina tool between the target protein with ligands. This research further showed that all the protease inhibitors accessed the target protein with negative dock energy. Molecular docking studies found that the natural coumarin analogue Inophyllum A showed an exceptional potential for inhibition with a binding energy of −8.4 kcal/mol. The synthetic coumarin analogues 1m and 1p both demonstrated a similar binding energy, inhibition potential of −7.9 kcal / mol as opposed to hydroxychloroquine and co-crystallized ligand alpha-ketoamide with binding energy values of −5.8 and −6.6 kcal / mol. All compounds evaluated were known as drug-like in nature, passing Lipinski's “Law of 5” with 0 violations except for alpha-ketoamide, passing Lipinski's “Rule of 5” with 1 violation (MW > 500). The inhibitor binding in silico research thus offers a structural understanding of COVID-19 and molecular interactions across the known protease inhibitors centred on the findings of the multiple sequence alliance.

Molecular dynamic mechanism(s) of inhibition of bioactive antiviral phytochemical compounds targeting cytochrome P450 3A4 and P-glycoprotein

P-glycoprotein (ABCB1) and cytochrome P450 3A4 (CYP3A4) metabolize almost all known human immunodeficiency virus' protease inhibitor drugs (PIs). Over induction of these proteins’ activities has been linked to rapid metabolism of PIs which are then pumped out of the circulatory system, eventually leading to drug-resistance in HIV-positive patients. This study aims to determine, with the use of computational tools, the inhibitory potential of four phytochemical compounds (PCs) (epigallocatechin gallate (EGCG), kaempferol-7-glucoside (K7G), luteolin (LUT) and ellagic acid (EGA)) in inhibiting the activities of these drug-metabolizing proteins. The comparative analysis of the MM/GBSA results revealed that the binding affinity (ΔGbind) of EGCG and K7G for CYP3A4 and ABCB1 are higher than LUT and EGA and fall between the ΔGbind of the inhibitors of CYP3A4 and ABCB1 (Ritonavir (strong inhibitor) and Lopinavir (moderate inhibitor)). The structural analysis (RMSD, RMSF, RoG and protein-ligand interaction plots) also confirmed that EGCG and K7G showed similar inhibitory activities with the inhibitors. The study has shown that EGCG and K7G have inhibitory activities against the two proteins and assumes they could decrease intracellular efflux of PIs, consequently increasing the optimal concentration of PIs in the systemic circulation. Communicated by Ramaswamy H. Sarma

Molecular Docking Evaluation of Some Indonesian’s Popular Herbals for a Possible COVID-19 Treatment

Indonesia’s rich tropical biodiversity offers many possible options for fighting the unprecedented outbreak of coronavirus disease 2019 (COVID-19). In this paper, we evaluate the in silico (molecular docking) performance of some popular herbal supplements and natural remedies, which are usually consumed by Indonesian people and compare them to the docking performance of the control ligand (N3 inhibitor) and some protease-inhibitor drugs. The tested active compounds were grouped based on their popularity in the market, i.e., honey, black seed (Nigella sativa), Javanese turmeric (Curcuma xanthorriza roxb), and mangosteen, which usually served in the form of encapsulated oil or powder. The results show that most of the tested active compounds perform better than N3 inhibitor and protease inhibitor drugs (lopinavir and darunavir) in inhibiting the main protease of SARS-CoV-2 virus of COVID-19 (C19MP). Based on the combined scores of binding affinity, the similarity of active sites (SAS), and the drug-likeness properties of the ligand, gamma mangostin turns out to be the best possible C19MP inhibitor as compared to other ligands. The active site analysis also reveals that His41, Met49, Leu141, and Asn142 are among the most important amino acids that play a significant role in the protein-ligand binding due to their frequent occurrence in the docking simulation.

Potential protease inhibitors and their combinations to block SARS-CoV-2

COVID-19, which has emerged recently as a pandemic viral infection caused by SARS-coronavirus 2 has spread rapidly around the world, creating a public health emergency. The current situation demands an effective therapeutic strategy to control the disease using drugs that are approved, or by inventing new ones. The present study examines the possible repurposing of existing anti-viral protease inhibitor drugs. For this, the structural features of the viral spike protein, the substrate for host cell protease and main protease of the available SARS CoV-2 isolates were established by comparing with related viruses for which antiviral drugs are effective. The results showed 97% sequence similarity among SARS and SARS-CoV-2 main protease and has same cleavage site positions and ACE2 receptor binding region as in the SARS–CoV spike protein. Though both are N-glycosylated, unlike SARS-CoV, human SARS-CoV-2 S-protein was O-glycosylated as well. Molecular docking studies were done to explore the role of FDA approved protease inhibitors to control SARS-CoV-2 replication. The results indicated that, Ritonavir has the highest potency to block SARS-CoV-2 main protease and human TMPRSS2, a host cell factor that aids viral infection. Other drugs such as Indinavir and Atazanavir also showed favourable binding with Cathepsin B/L that helped viral fusion with the host cell membrane. Further molecular dynamics simulation and MM-PBSA binding free energy calculations confirmed the stability of protein-drug complexes. These results suggest that protease inhibitors particularly Ritonavir, either alone or in combination with other drugs such as Atazanavir, have the potential to treat COVID 19. Communicated by Ramaswamy H. Sarma

Molecular Modeling Analyses for Modified Biopolymers

Biopolymer blends and structural modifications with phenol and hydroxymethylcarbonyl (HMC) are studied to show the ability to interact with amino acids as promising to act as HIV protease inhibitors. Chitosan (Cs), cellulose (Cel), starch (Str) and gelatin (Gel) as well as their blends as Cs/Cel; Cs/Str; Cs/Gel with ratios 3:1; 2:2; 1:3 were subjected to molecular modeling. These biopolymers, as well as their blends, are calculated with quantum mechanical calculations at PM6 level of theory. QSAR, surface area, and volume properties of the interaction of phenol and HMC upon Cs/Cel; Cs/Str; Cs/Gel in the different positions of the four units are calculated at the same level of theory. QSAR descriptors for studied polymers show a change in their physical properties as result of blending. Depending on QSAR calculations, the interaction of phenol and HMC with Cs/Cel and Cs/Str blends for ratio 1:3 through the first unit increases the reactivity of these modified structures. The solubility of modified blends is increased by increasing chitosan units in the proposed modified blends. The surface area of modified Cs/Cel ratios increases comparing with modified Cs/Str and Cs/Gel ratios. This recommends the modified blends of Cs/Cel ratio can be used as promising HIV protease inhibitors drugs.

Binding site analysis of potential protease inhibitors of COVID-19 using AutoDock.

Recent outbreak of COVID-19 caused by SARS-CoV-2 in December 2019 raised global health concerns. Re-purposing the available protease inhibitor drugs for immediate use in treatment in SARS-CoV-2 infections could improve the currently available clinical management. The current study, aims to predict theoretical structure for protease of COVID-19 and to explore further whether this protein can serve as a target for protease inhibitor drugs such as remdesivir, nelfinavir, lopinavir, ritonavir and α-ketoamide. While the 3D structure of protease was predicted using SWISS MODEL server, molecular interaction studies between protein and ligands were performed using AutoDock software. The predicted protease model was reasonably good based on reports generated by different validation servers. The study further revealed that all the protease inhibitor drugs got docked with negative dock energy onto the target protein. Molecular interaction studies showed that protease structure had multiple active site residues for remdesivir, while for remaining ligands the structure had only one active site residue each. From the output of multiple sequence alignment, it is evident that ligand binding sites were conserved. The current in silico study thus, provides structural insights about the protease of COVID-19 and also its molecular interactions with some of the known protease inhibitors.Electronic supplementary materialThe online version of this article (10.1007/s13337-020-00585-z) contains supplementary material, which is available to authorized users.

Natural Bioactive Compounds from Fungi as Potential Candidates for Protease Inhibitors and Immunomodulators to Apply for Coronaviruses.

The inhibition of viral protease is an important target in antiviral drug discovery and development. To date, protease inhibitor drugs, especially HIV-1 protease inhibitors, have been available for human clinical use in the treatment of coronaviruses. However, these drugs can have adverse side effects and they can become ineffective due to eventual drug resistance. Thus, the search for natural bioactive compounds that were obtained from bio-resources that exert inhibitory capabilities against HIV-1 protease activity is of great interest. Fungi are a source of natural bioactive compounds that offer therapeutic potential in the prevention of viral diseases and for the improvement of human immunomodulation. Here, we made a brief review of the current findings on fungi as producers of protease inhibitors and studies on the relevant candidate fungal bioactive compounds that can offer immunomodulatory activities as potential therapeutic agents of coronaviruses in the future.

Development of A Fission Yeast Cell-Based Platform for High Throughput Screening of HIV-1 Protease Inhibitors.

HIV-1 protease inhibitor (PI) is one of the most potent classes of drugs in combinational antiretroviral therapies (cART). When a PI is used in combination with other anti- HIV drugs, cART can often suppress HIV-1 below detection thus prolonging the patient's lives. However, the challenge often faced by patients is the emergence of HIV-1 drug resistance. Thus, PIs with high genetic-barrier to drug-resistance are needed. The objective of this study was to develop a novel and simple fission yeast (Schizosaccharomyces pombe) cell-based system that is suitable for high throughput screening (HTS) of small molecules against HIV-1 protease (PR). A fission yeast RE294-GFP strain that stably expresses HIV-1 PR and green fluorescence protein (GFP) under the control of an inducible nmt1 promoter was used. Production of HIV-1 PR induces cellular growth arrest, which was used as the primary endpoint for the search of PIs and was quantified by an absorbance-based method. Levels of GFP production were used as a counter-screen control to eliminate potential transcriptional nmt1 inhibitors. Both the absorbance-based HIV-1 PR assay and the GFP-based fluorescence assay were miniaturized and optimized for HTS. A pilot study was performed using a small drug library mixed with known PI drugs and nmt1 inhibitors. With empirically adjusted and clearly defined double-selection criteria, we were able to correctly identify the PIs and to exclude all hidden nmt1 inhibitors. We have successfully developed and validated a fission yeast cell-based HTS platform for the future screening and testing of HIV-1 PR inhibitors.

Hepatitis C Virus Drugs Simeprevir And Grazoprevir Synergize with Remdesivir to Suppress SARS-CoV2 Replication

Effective control of COVID-19 requires antivirals directed against SARS-CoV-2 virus. Here we assess ten available HCV protease inhibitor drugs as potential SARS-CoV-2 antivirals. There is a striking structural similarity of the substrate binding clefts of SARS-CoV-2 Mpro and HCV NS3/4A proteases, and virtual docking experiments show that all ten HCV drugs can potentially bind into the Mpro binding cleft. Seven of these HCV drugs inhibit SARS-CoV-2 Mpro protease activity, while four dock well into the PLpro substrate binding cleft and inhibit PLpro protease activity. These same seven HCV drugs inhibit SARS-CoV-2 virus replication in Vero and/or human cells, demonstrating that HCV drugs that inhibit Mpro, or both Mpro and PLpro, suppress virus replication. Two HCV drugs, simeprevir and grazoprevir synergize with the viral polymerase inhibitor remdesivir to inhibit virus replication, thereby increasing remdesivir inhibitory activity as much as 10-fold.Funding: This research was supported by grants from the National Institutes of Health (R01-GM120574 to GTM) and RPI Center for Computational Innovations (to KB and GTM). This research was also partly funded by CRIP (Center for Research for Influenza Pathogenesis), a NIAID supported Center of Excellence for Influenza Research and Surveillance (CEIRS, contract #,HHSN272201400008C), by DARPA grant HR0011-19-2-0020, by supplements to NIAID grant U19AI142733 U19AI135972 and DoD grant W81XWH-20-1-0270, and by the generous support of the JPB Foundation, the Open Philanthropy Project (research grant 2020-215611 (5384)), and anonymous donors to AG-S.Conflict of Interest: A provisional patent application related to these, studies has been filed. GTM is a founder of Nexomics Biosciences, Inc. This, relationship has no conflict of interest with respect to this study. GTM and RMK are inventors in patents owned jointly by Rutgers University and the University of Texas at Austin concerning the use of specific compounds as antivirals against influenza virus. These patents have no conflict of interest for this study. AG-S is inventor in patents and patent application owned by the Icahn School of Medicine concerning the use of specific antiviral compounds. This inventorship has no conflict of interest with respect to this study.

Genital secretion HIV RNA shedding in HIV-positive patients on ritonavir-boosted protease inhibitor monotherapy or standard combination ART: a cross-sectional sub-study from the PIVOT Trial.

Protease inhibitors (PI) have relatively low penetration into the genital tract, raising concerns about the potential for genital HIV RNA shedding in patients taking PI-based regimens, particularly PI monotherapy (PI-mono). We measured HIV RNA and PI drug concentrations in samples of semen, cervico-vaginal and rectal mucosa secretions, and plasma in patients after 48-96 weeks on PI-mono or standard triple therapy. A total of 85 participants were recruited. Of the 43 participants on PI-mono (70% on darunavir [DRV]/ritonavir [r]), 3 had detectable virus in semen or vaginal secretions (all below quantification limit), and none in rectal mucosa or plasma. Among those taking triple therapy, five had detectable virus in semen or vaginal secretions (HIV RNA >50 copies/ml in one), none in rectal mucosa and one in plasma. The median (IQR) concentration of DRV and atazanavir in semen (659.7 [339-1,089] and 128.8 [63-368] ng/ml, respectively) and cervico-vaginal samples (2,768 [312-7,879] and 1,836 [359-3,314] ng/ml, respectively) exceeded their protein adjusted median inhibition concentration (MIC50). DRV concentration in rectal secretions showed higher variability compared with concentration in the other sites, with particularly high rectal secretion/blood ratios (median 8.4, IQR 2.6-68.7:1). We found no substantive evidence of HIV shedding in patients taking PI-mono, suggesting that PIs provide adequate control of virus in the genital compartment and are unlikely to lead to ongoing sexual transmission.

Protease Inhibitors for the Treatment of HIV/AIDS: Recent Advances and Future Challenges.

Acquired Immunodeficiency Syndrome (AIDS) is a chronic disease characterized by multiple life-threatening illnesses caused by a retro-virus, Human Immunodeficiency Virus (HIV). HIV infection slowly destroys the immune system and increases the risk of various other infections and diseases. Although, there is no immediate cure for HIV infection/AIDS, several drugs targeting various cruxes of HIV infection are used to slow down the progress of the disease and to boost the immune system. One of the key therapeutic strategies is Highly Active Antiretroviral Therapy (HAART) or ' AIDS cocktail' in a general sense, which is a customized combination of anti-retroviral drugs designed to combat the HIV infection. Since HAART's inception in 1995, this treatment was found to be effective in improving the life expectancy of HIV patients over two decades. Among various classes of HAART treatment regimen, Protease Inhibitors (PIs) are known to be widely used as a major component and found to be effective in treating HIV infection/AIDS. For the past several years, a variety of protease inhibitors have been reported. This review outlines the drug design strategies of PIs, chemical and pharmacological characteristics of some mechanism-based inhibitors, summarizes the recent developments in small molecule based drug discovery with HIV protease as a drug target. Further discussed are the pharmacology, PI drug resistance on HIV PR, adverse effects of HIV PIs and challenges/impediments in the successful application of HIV PIs as an important class of drugs in HAART regimen for the effective treatment of AIDS.

The pharmacokinetic properties of HIV-1 protease inhibitors: A computational perspective on herbal phytochemicals

Acquired Immune Deficiency Syndrome is the most severe phase of Human Immunodeficiency Virus (HIV) infection. Recent studies have seen an effort to isolate phytochemicals from plants to repress HIV, but less studies have focused on the effects of these phytochemicals on the activities of enzymes/transporters involved in the metabolism of these drugs, which is one of the aims of this study and, to examine the antiviral activity of these compounds against HIV-1 protease enzyme using computational tools. Centre of Awareness-Food Supplement (COA®-FS) herbal medicine, has been said to have potential anti-HIV features. SWISSTARGETPREDICTION and SWISSADME servers were used for determination of the enzymes/transporters involved in the metabolism of these protease inhibitor drugs, (PIs) (Atazanavir, Lopinavir, Darunavir, Saquinavir) and the effects of the selected phytochemicals on the enzymes/transporters involved in the metabolism of these PIs. Using Computational tools, potential structural inhibitory activities of these phytochemicals were explored. Two sub-families of Cytochrome P450 enzymes (CYP3A4 and CYP2C19) and Permeability glycoprotein (P-gp) were predicted to be involved in metabolism of the PIs. Six phytochemicals (Geranin, Apigenin, Fisetin, Luteolin, Phthalic acid and Gallic acid) were predicted to be inhibitors of CYP3A4 and, may slowdown elimination of PIs thereby maintain optimal PIs concentrations. Free binding energy analysis for antiviral activities identified four phytochemicals with favourable binding landscapes with HIV-1 protease enzyme. Epigallocatechin gallate and Kaempferol-7-glucoside exhibited pronounced structural evidence as potential HIV-1 protease enzyme inhibitors. This study acts as a steppingstone toward the use of natural products against diseases that are plagued with adverse drug-interactions.

An improved and robust scale-up process aided with identification and control of critical process impurities in darunavir ethanolate

A robust and safe industrial process, including five isolations and drying steps for widely prescribed anti-HIV (protease inhibitor) drug darunavir ethanolate 2, has been developed. A salient feature of this process is the development of procedures enabling the efficient synthesis of multi-kilogram quantity of darunavir ethanolate, and process demonstrations through plant scale preparation are offered where darunavir molecule has been prepared with overall > 70% chemical yield and > 99.8% purity without involving any purification procedure(s), with all possible process impurities below than the desired limit (not more than 0.08%) were isolated, synthesized and characterized. The developed process is entirely robust, very efficient and demonstrated up to kilograms scale.

Discovery and Rational Design of a Novel Bowman-Birk Related Protease Inhibitor.

Anuran amphibian skin secretions are a rich source of peptides, many of which represent novel protease inhibitors and can potentially act as a source for protease inhibitor drug discovery. In this study, a novel bioactive Bowman-Birk type inhibitory hexadecapeptide of the Ranacyclin family from the defensive skin secretion of the Fukien gold-striped pond frog, Pelophlax plancyi fukienesis, was successfully isolated and identified, named PPF-BBI. The primary structure of the biosynthetic precursor was deduced from a cDNA sequence cloned from a skin-derived cDNA library, which contains a consensus motif representative of the Bowman-Birk type inhibitor. The peptide was chemically synthesized and displayed a potent inhibitory activity against trypsin (Ki of 0.17 µM), as well as an inhibitory activity against tryptase (Ki of 30.73 µM). A number of analogues of this peptide were produced by rational design. An analogue, which substituted the lysine (K) at the predicted P1 position with phenylalanine (F), exhibited a potent chymotrypsin inhibitory activity (Ki of 0.851 µM). Alternatively, a more potent protease inhibitory activity, as well as antimicrobial activity, was observed when P16 was replaced by lysine, forming K16-PPF-BBI. The addition of the cell-penetrating peptide Tat with a trypsin inhibitory loop resulted in a peptide with a selective inhibitory activity toward trypsin, as well as a strong antifungal activity. This peptide also inhibited the growth of two lung cancer cells, H460 and H157, demonstrating that the targeted modifications of this peptide could effectively and efficiently alter its bioactivity.

Characterisation of protease resistance mutations in a South African paediatric cohort with virological failure, 2011 - 2017.

Advances in HIV management have improved treatment outcomes in the HIV-infected population. However, these advances have not been without multifaceted challenges. In sub-Saharan Africa, their impact is reflected in the increased emergence of HIV drug resistance mutations. With the rise in exposure of children to protease inhibitors (PIs), the possibility of increasing PI resistance remains a concern. To describe a group of antiretroviral-experienced children with PI drug resistance mutations after failure on first- or second-line regimens in a public sector setting in South Africa. This was a retrospective cohort study of 22 children perinatally infected with HIV who had HIV genotyping conducted between January 2011 and December 2017. Of the 236 children who had HIV genotyping conducted, 22 (9.3%) had evidence of HIV PI resistance mutations. Twenty-one of the 22 children (95.5%) had major mutations in the protease region of the HIV genome. Of these children, 66.7% (14/21) had loss of response to both boosted lopinavir and atazanavir, with boosted darunavir remaining susceptible in only 12 (57.1%). The most frequent major PI mutations were V82A (76.2%), M46I/M46L (76.2%), I54V (62.0%) and L76V (33.3%). We observed a high rate of PI resistance mutations, with a resulting loss of PIs that could be used in construction of third-line regimens. To build on improvements from the introduction of antiretroviral therapy, increased efforts are needed by both health professionals and caregivers to improve adherence measures in children perinatally infected with HIV.

Assay of tipranavir capsules by a simple stability-indicating LC–UV method and cytotoxicity study of degraded samples

Tipranavir (TPV) is a protease inhibitor (PI) specially recommended for treatment-experienced patients who are resistant to other PI drugs. It was approved by FDA in 2005, but, until now, it has not been included in any official compendia. The objective of this study is to develop and validate a simple LC–UV method to assay TPV capsules, and to study the cytotoxicity of TPV and degraded samples over the cell viability. The optimized conditions were C8 Phenomenex® column (Luna®, 150 mm × 4.6 mm, 5 µm); mobile phase composed by methanol, acetonitrile, and acidified water pH 3.5 (40:31:29); flow rate 1.0 mL min−1 and detection at 254 nm. The cytotoxic effects of non-degraded and degraded TPV samples were evaluated in 3T3 cells by means of MTT viability assay. The method was linear in the range of 10–100 µg mL−1 (r = 0.9999) and specific, even in the presence of degradation products and impurities. The method showed suitable accuracy (mean recovery 100.02%), precision (RSD < 1.10%), and a two-level full factorial design indicated the robustness of the method. The degraded samples exhibited cytotoxicity patterns similar to TPV under controlled conditions. The method developed is appropriate for quality control of TPV capsules and stability studies.

Quantification of fosamprenavir in spiked human plasma using liquid chromatography–electrospray ionization–tandem mass spectrophotometry–application to pharmacokinetic study

Background Fosamprenavir (FSV) is used for the treatment of HIV infections. It is a prodrug of the protease inhibitor and antiretroviral drug amprenavir. Aim This research work described about the estimation of FSV in spiked human plasma using electrospray ionization, LC-MS/MS technique, and its application to pharmacokinetic study in rabbits. Materials and methods Liquid–liquid extraction technique was used for the extraction of FSV in spiked human plasma. The separation was achieved using ZORBAX SB-C18 column with 4.6 mm internal diameter with 5 μm particle size using acetonitrile: 5 mmol/l ammonium acetate in water (85 : 15, v/v) as a mobile phase. Positive ion mode was selected for the product ion mass spectra, m/z 585.6–418.2 for FSV and m/z 589.2–469.1 for FSV-deuterated (internal standard), The US Food and Drug Administration guidelines were adopted for successful validation of the developed method. Results The retention time of FSV was found to be 1.51 min, for FSV-deuterated it was 1.62 min, with a runtime of 2.5 min. The present method exhibits excellent intraday and interday accuracy with %nominal 95–98.4% and precision percentage coefficient variation up to 3% in all quality control (QC) levels. The developed method demonstrated excellent matrix and analyte selectivity (%interference=0), matrix effect (matrix factor 2.09 at lower quantitation limit and 1.14 at high QC level) and satisfactory stability study results in all types (%nominal 94.03–100.80%). The linearity range was found to be 0.510–200.185 ng/ml with a correlation coefficient (r2) of 0.998. The calculated accuracy and precision values in the ruggedness study were within 15–20% in all QC levels. The percentage coefficient variation of the pharmacokinetic study on rabbit plasma samples was also conducted and the parameters of FSV showed Tmax of 2 h and the mean Cmax, AUC0→t and AUC0→α for test formulation were 98.6, 351.3, and 354.9, respectively. Conclusion This method was successfully optimized, validated, and applied favorable for the pharmacokinetic study of marketed formulation in rabbit blood samples in a single oral human-equivalent dose. The applicability of the developed method undoubtedly can further extend during preclinical and clinical trials.